Protein can be found in animal meats, eggs, and nuts to name a few. Not all these proteins are the same. Each have a different bio-availabilities. They are absorbed and used in unique ways in the body.
The amount of protein in the human diet has a large effect on body composition. The modern view is “More Protein the Better”. This idea comes from the body builders of the 80’s who consumed large amounts of protein to grow their muscles to huge proportions. Although protein is necessary for cellular growth, there are diminishing returns on protein consumption.
Low quality protein shakes are prolific currently. Seeing shakers in the gym have become commonplace. The truth is, that kind of protein is not built the same as Salmon, for example. Excess protein can be converted to glucose in the body. Extra glucose will be stored as fats.